I. Field
The present disclosure relates generally to communication, and more specifically to filtering techniques.
II. Background
In a wireless communication system, a transmitter typically processes (e.g., encodes and modulates) traffic data to generate data symbols. For a coherent system, the transmitter multiplexes pilot symbols with the data symbols, processes the multiplexed data and pilot symbols to generate a radio frequency (RF) signal, and transmits the RF signal via a wireless channel. The wireless channel distorts the transmitted RF signal with a channel response and further degrades the signal with noise and interference.
A receiver receives the transmitted RF signal and processes the received RF signal to obtain samples. For coherent data detection, the receiver estimates the response of the wireless channel based on the received pilot and derives a channel estimate. The receiver then performs data detection (e.g., equalization) on the samples with the channel estimate to obtain symbol estimates, which are estimates of the data symbols sent by the transmitter. The receiver then processes (e.g., demodulates and decodes) the symbol estimates to obtain decoded data.
The quality of the channel estimate may have a large impact on data detection performance and may affect the quality of the symbol estimates as well as the reliability of the decoded data. There is therefore a need in the art for techniques to derive a high quality channel estimate in a wireless communication system.